1. Field of the Invention
A novel internal combustion engine which operates at low temperature with high fuel energy utilization efficiency.
2. The Prior Art
The growing utilization of automobiles greatly adds to the presence in the atmosphere of various pollutants including greenhouse gases such as carbon dioxide, which circumstances have led to a quest for approaches to improve the efficiency of fuel utilization for automotive powertrains.
Conventional internal combustion engines (ICE's) used in passenger vehicles average about 15% thermal efficiency in urban driving and have peak efficiencies of about 35%. Even at peak efficiency, current engines discard almost two thirds of the heat energy supplied to them, i.e. through the engine coolant system and through the exhaust gas. The chemical energy contained in fuel is converted into heat energy when it is burned in an engine. Since this combustion takes place in a closed volume (the combustion chamber of the engine), the increased temperature of the combustion gases (and in some cases the increased number of moles of the combustion gases as compared to the reactants) results in an increase in pressure of the system. As the volume of the combustion chamber expands, e.g. the piston moves, work is performed. Conventional internal combustion engines waste much of the available heat energy. First, the combustion chamber is cooled by liquid or air, thus reducing pressure and the potential for work. Second, the expansion process does not allow for full expansion or for full utilization of the pressure developed in the combustion chamber, as the expansion ratio is usually limited by the compression ratio. Third, a considerable amount of heat remains in the exhaust gas.